Synchronizing internal combustion engine



Feb. 15, 1938. c. K. WOODMAN I SYNCHRONIZING INTERNAL COMBUSTION ENGINE Filed Sept. 28, 1936 In venfor" Patented Feb. 15, 1938- UNITED STATES PATENT OFFICE SYNCHRONIZING INTERNAL COMBUSTION ENGINE '7 Claims.

The present invention relates to improvements in synchronizing internal combustion engines having the usual equipment of circuit breaker and spark plug or other ignition device. In one aspect it consists in a method of synchronizing internal combustion engines which consists in causing a circuit breaker of one engine to control the ignition of the other engine. In another aspect it consists in a system including a switch or other controlling device arranged in one position to direct the ignition current from the breaker of one engine to its own spark plugs, and in another position for directing current from the breaker of one engine to the spark plugs of the other.

While my invention has a broad field of application to any multiple installation of internal combustion engines, an important field of use is in connection with motor boat installation where a pair of internal combustion engines are independently connected to twin propellers. For many reasons it is desirable to operate such engines in synchronism, not only because the boat is easier to handle in these conditions, but because an unpleasant beat is developed when the engines are not synchronized. The present practice is to provide independent mechanism for controlling the speed of the two engines with an indicator for visually showing individual speeds. Such an installation requires almost constant vigilance on the part of the navigator and even when the speed of the two engines is synchronized there is a constant tendency toward variation under normal sailing conditions, as for example, when more load is thrown on one engine than the other in changing the course of the boat. I have discovered that two engines may be caused to run synchronously even under conditions involving considerable variation in load by crossing the ignition circuits in such a manner as to cause the breaker of one engine to control the time of ignition of the other engine. In practice the two engines may be independently brought up to substantially the same speed and then the cross-over connection efiected. Runnin'g' under this system it will be apparent that if one'engine is caused to slow down on account of increased load or for any other reason, the ignition timing in the other engine is retarded and the speed of the engine correspondingly reduced. These and other features of the invention will be best understood and appreciated from the following description of a preferred embodiment thereof, selected for purposes of illustration and shown in the accompanying drawing in which;-

The figure is a diagrammatic view of the system as embodied in an installation comprising the two engines of a motor boat.

In the drawing a portion l and a portion 38 of the port and starboard engine cylinders are shown as equipped with spark plugs H and 3|, connected in high tension circuit by wires l2 and 32 respectively to the covers l3 and 33 of two distributors. Similarconnections may extend from the distributors to other cylinders, not shown, and in these distributors the rotor M or is driven in fixed time relation by its respective engine. The distributor l3 has a connection I5 to the spark coil l6 of the port engine, and the distributor 33 has a connection 35 to the spark coil 36 of the starboard engine. The engines are further provided with independent ignition switches l1 and 31 and with individual breakers 23 and 43 which are'included in their respective primary or low tension circuits.

In the installation shown the current is supplied by a single battery 26 having a ground connection 21. The battery is connected to the port engine through its ignition switch ll by wires 28- and I8 and to the starboard engine through the switch H by wires 28 and 38. The low tension side of the spark coil I6 is connected through a wire I9 to one terminal 20 of a four-pole switch 41 having a movable member which includes two separate insulated segments 44 and 45 and a switch lever 48, the whole switch being arranged within convenient range of the navigator. The second terminal 2| of the switch is connected by a wire 22 to the breaker 23 of the port engine. The breaker is grounded by the connection 24 and the cylinder ID by the connection 25 in high tension circuit.

Similarly the low tension side of the spark coil 36 is connected by a wire 39 to the third terminal 40 of the switch 41. The fourth terminal 4| of the switch is connected by a Wire 42 to the breaker 43 of the starboard engine, and this in turn is grounded by the connection 46 and the cylinder 30 is grounded by the connection 45 in high tension circuit.

In the position illustrated in the drawing the switch member occupies a position in which the segment 44 connects the terminals 40 and 4| and the segment 45 connects the terminals 20 and 2|. The switches l1 and 31 are also shown in closed condition so that current from the battery 26 flows through the primary circuit of each spark coil and through the breaker for the respective engines. That is, the current flows from the bat-- tery 26, through the connections 28, I8, the switch I! to the spark coil l6, of the port engine, then through the connection Hi to terminal 20, through the segment 45 to terminal 2|, through the connection 22 to the breaker 23 of the port engine and through the connection 24 to the ground, that is to say, to the engine frame. Accordingly, whenever the circuit is broken in the rotation oi. the breaker cam in the breaker 23 a high tension current is induced into the secondary circuit and a spark occurs in the spark plug II of the port engine.

Similarly current flows from the battery 26 through the connections 23, 38, switch 31, through the primary connection of the spark coil 36, to the connection 39, terminal 40, segment 44, terminal 4|, connection 42 to the breaker 43 of the starboard engine and through the connection 46 to the ground. Accordingly when the primary circuit is broken in the rotation of the breaker cam of the breaker 43 a high tension current is induced in the secondary circuit of the spark coil 36 and a spark occurs in the spark plug 3| of the starboard engine. That is, both engines are operating independently, each breaker controlling the time of. ignition in the engine with which it is associated. Under these 1 conditions the two engines may be independently brought up to the same speed by manipulating their respective throttles or in any other desired.

manner. Having brought the two engines to substantially the same speed, the navigator may now throw the switch lever 48, 90 to the left as shown in the drawing thus interrupting the circuit between the terminals 2|l--2| and 4ll4| and closing a circuit between the terminals 204| and 2|-40. In this shift the individual switches I! and 31 are left undisturbed. The cross-over connection thus established has the effect of putting the breaker 23 of the port engine in control of the timing of the spark plug 3| of the starboard engine, and of putting the breaker 43 of the starboard engine in control of the timing of the spark plug oi. the port engine. The current from the battery 26 now flows through the connections 28, I8, switch I1, to the spark coil l6 of. the port engine, and then through the connection l9, terminal 2!], segment 44, terminal 4|, connection 42 to the breaker 43 of the starboard engine. Accordingly when the primary circuit of the spark coil I6 is interrupted by the breaker 43 a spark occurs in the spark plug H of the port engine. Current also flows from the battery 26 through the connections 28, 38, switch 31, to the spark coil 35 of the starboard engine, and from there through the connection 39, terminal 40, segment 45, terminal 2|, con-'- nection 22 to the breaker 23 of the port engine. Accordingly when in the rotation of the breaker cam of the breaker 23 the primary circuit is interrupted in the spark coil 36, a spark occurs in the spark plug 3| of the starboard engine. I

Running with the cross-over connections thus established, the two engines will be practically locked in step and will continue in synchronous operation under all normal conditions of sailing. For example, the boat may be made to swing as sharply as possible in either direction without disturbing the synchronous operation of the two engines. The navigator is thus relieved of the necessity of constant vigilance and attention to the speed of the separate engine, and may handle the boat with no more complication than is required by a single engine.

It will be understood that the installation may include any type of commercial indicator for showing the speed of the individual engines, but since these form no part of the present invention they are not herein illustrated. As amatter of fact however, it requires little experience to use the beat of the two engines as an indication of the proper time for throwing, the cross-over switch. This may be done at the peak of the beat thus obviating the necessity of getting the engines into perfect synchronism by use of the individual throttles.

While I have described specifically a motor boat installation including a pair oi engines using gasoline fuel the invention may be advantageously applied to any multiple installation of internal combustion engines where synchronous operation is desirable, as in airplanes, for example. It may also be applied to other types of internal combustion engines than those shown, such as rotary engines or engines of the Diesel type, all being within the scope of the invention.

Having thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is,-

1. The method of synchronizing a pair of internal combustion engines, which consists in causing a circuit breaker of one engine to control the ignition of the other engine.

2. The method of synchronizing a pair of internal combustion engines, which consists in independently bringing the two engines up to approximately the same speed, and then so connecting the ignition circuits of the two engines that a circuit breaker of. one controls the time of ignition in the other. 3. The method of synchronizing internal combustion engines, which consists in independently bringing the engines up to approximately the same speed while the circuit breaker of each engine controls its own time of ignition, and then suddenly crossing the ignition circuits so that the circuit breaker of one controls the time of ignition of the other.

4. A system for synchronizing internal combustion engines each equipped with a breaker and a spark plug, which comprises electrical connections and a multiple pole switch arranged in one position for directing current to flow from the breaker of one engine to its own spark plug, and in another position for directing current to flow from the breaker of. one engine to the spark plugs of the other engine.

; 5. A system. for synchronizing internal combustion engines each equipped with a breaker, an ignition device and a spark coil, which comprises electrical connections and a multiple pole-switch arranged in one position to direct current from the breaker of one engine through its own coil and to its own ignition device, and in another position to direct current from the breaker of one :engine through the coil and to the ignition device of the other engine.

6. A system for synchronizing internal engines each equipped with a breaker and an ignition device, which comprises a battery, electrical connections and a multiple pole switch arranged in one position to direct current from the battery to the breaker of each engine and to itsown,

ignition device, and in another position to direct current from the battery to the breaker of each engine and to the ignition device of another engine.

7. A system for synchronizing internal combustion engines each equipped with a rotary timing device and a plurality of spark plugs and having electrical connections, and a switch device arranged in one position for directing the current to flow from the rotary timing device of each engine to its own series of spark plugs, and

I in another position for directing current to flow from the rotary timing device of each engine to the series of spark plugs of the other engine.

CHARLES K. WOODMAN. 

